XP: ab workout question

pkaren

I do an aerobics class 3x/week and I'm wondering if I should continue with the ab workout the instructor does or if I should be modifying. I've been doing this class for over a year, so it's not new to me. I did the whole thing today and felt fine, but I'm wondering at what point I should stop laying on my back and doing regular crunches. I'm thinking I'll just know when to not do it anymore bc it'll start to get uncomfortable? Or should I start skipping out on the ab workouts now and do my own preg safe core workouts?

TIA Ladies!